Background and objective Studies showed that atherosclerosis is a systemic disease. Parameters representing peripheral artery atherosclerosis, such as decreased ankle-brachial index (ABI), and increased carotid artery intima-media thickness (CIMT), are well correlated with coronary artery disease. However, these are indirect indicators provided by ultrasound examination. Eyes are good windows, through which we can observe vascular anatomy and function in vivo directly and clearly. Our study was to explore the correlation of retinal vascular diameter and arteriole-to-venule ratio (AVR) on the retinal photographs to extent and severity of coronary artery disease (CAD) angiographically.
Methods From January 2007 to February 2008, the patients admitted in CCU and Department of Cardiovascular Disease of Beijing Chuiyangliu Hospital with diagnosed or suspected of CAD were selected to accept coronary artery angiography using standard Judikin's technique. According to Gensini score, the degree and extent of coronary atherosclerosis were visually evaluated and scored by 2 expert cardiologists. The calibres of individual retinal arteriole and venule coursing through a zone located at 1 to 1.5 disc diameter from the optic disc margin were measured on the digital retinal photographs using a computer-assisted method by two trained oculists who had no knowledge of the patients’ condition of coronary artery angiogram, and the arteriole-to-venule ratio was calculated.
Results 1. 114 patients were enrolled, including 61 men and 53 women, aged from 34 to 82 years (60.16±10.34 y). The diagnosis of CAD was confirmed in 85 patients (CAD group) and the other 29 patients with negative results (control group) angiographically. There were no significant differences between two groups in terms of baseline clinical characteristics. 2. The result of coronary artery angiography: 85 patients (74.57%) were diagnosed as CAD, and the other 29 patients (25.43%) were excluded from CAD. In CAD group, the severity of the coronary lesions was assessed by Gensini scoring system, a method that assigns a different severity score depending on the degree of luminal narrowing and the geographical importance of their locations. 25 patients scored −40, 26 patients scored 41–80, 23 cases scored 81–120, and 11 cases scored greater than 120.3. The results of the retinal vascular measurement and calculation: The mean retinal arteriole diameter (upper temporal branch and inferior temporal branch) in CAD group was significantly smaller than that in control group (p<0.05). The mean retinal venule diameter (upper temporal branch and inferior temporal branch) in CAD group was significantly greater than that in control group (p<0.05). The mean retinal AVR (both in upper temporal branch and inferior temporal branch) in CAD group was much smaller than that in control group (p<0.05). 4. The correlation analysis between retinal vascular diameter, AVR and the severity of coronary atherosclerosis: the numerical values of retinal artery diameter and AVR in patients with Gensini score group 81–120 and >120 were significantly smaller than that with Gensini score ≦40 (p<0.05), but the calibre of retinal venule in patients with Gensini score group 81–120 and >120 was significantly greater than that with Gensini score ≦40 (p<0.05), there were no significant differences between the other groups. With Pearson correlation analysis to analyse the correlation of retinal AVR to Gensini score, the result showed that in CAD patients, the retinal AVR was negatively correlated to the Gensini score (p<0.01), With partial correlation analysis and controlling of other influencing factors, such as hypertension and diabetes, the negtive correlation didn't change.
Conclusion In our study, the retinal vascular diameter and AVR are well correlated to the severity of coronary artery disease. In CAD patients, the retinal arteriole calibre and AVR are significantly negatively correlated to Gensini score, and the retinal venule diameter is strongly positively correlated to Gensini score.